Ic card

ABSTRACT

The present invention includes an IC card that can realize high function without increasing the size of an IC chip, and that can realize cost reduction. The IC card has a first single crystal integrated circuit, a second integrated circuit, and a display device. The second integrated circuit and the display device are each formed from a thin film semiconductor film, over a plastic substrate, and the first single crystal integrated circuit is mounted on the plastic substrate so as to be electrically connected to the second integrated circuit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an IC card (which is also called asmart card) incorporating an integrated circuit such as a memory or amicroprocessor (CPU), and a display device that can display an image.

2. Description of the Related Art

Several ten bytes of data only can be memorized in a magnetic card thatcan memorize data magnetically. However, an IC card (an electronic card)incorporating a semiconductor memory, normally, can memorize about 5 KBof data or more. The IC card can assure much more capacity than amagnetic card. Further, the IC card has merits that the IC card does nothave a risk that data is read out by a physical means such as puttingiron sand on the card, different from a magnetic card, and that datamemorized in the IC card is not easily falsified.

It is noted that a category of a card typified by an electronic cardincludes an ID card to serve as an identification paper, a semi hardcard having flexibility such as a plastic card, and the like.

In recent years, an IC card has a higher function by being provided withan integrated circuit such as a CPU as well as a memory. The applicationthereof is wide-ranging, for example, it is applied to an ATM card, acredit cart, a prepaid card, a patient's registration card, an identitycard such as a student card or an employee ID card, a season ticket, amembership card, etc. As an example of the high function, an IC card forwhich a display device that can display simple characters and numbers isprovided and for which a keyboard to input numbers is provided isdescribed in Reference 1 (Reference 1: Japanese Examined PatentPublication No. H2-7105).

As described in Reference 1, a new use becomes possible by adding a newfunction to an IC card. Nowadays, electronic commerce, teleworking,remote medical care, remote education, computerized administrativeservices, automatic toll revenue from an expressway, image distributionservice and the like using an IC card are to be put to a practical useand it is considered that an IC card will be used in a wider field inthe future.

By the way, an integrated circuit used for an IC card is formed from achip (referred to as IC chip) using a single crystal semiconductorsubstrate and is mounted on the IC card. The thickness of an IC card isgenerally about 0.76 mm, whereas the thickness of an IC chip is severalhundred μm. Therefore, there is naturally a limitation on the size of anIC chip in holding the intensity for bending of an IC card to someextent. Accordingly, it is difficult to mount much more integratedcircuits that are larger in a circuit scale or a memory capacity, on anIC chip having a limitation on its size, thereby preventing theintegrated circuits from having higher functions.

Cost reduction of an IC card is also an important object to spread an ICcard in a wider field.

As an IC card is used more widely, a misapplication of an IC cardbecomes a bigger problem measurably. A future issue is how securelyidentification is performed when an IC card is used. Printing a pictureof a face on an IC card is one of measures for preventing themisapplication of the IC card. It is possible, by printing a picture ofa face, that a third person can identify a person to be identified at aglance when the person uses his/her IC card, if such identification isnot performed in an unattended terminal operation such as ATM. Amisapplication can be prevented efficiently in the case where a securitycamera that can take a picture of a user's face at close range is notprovided. However, in general, a picture of a face is transferred on anIC card by a printing method, and thus there is a pitfall that thepicture of the face is easily changed by forgery.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an IC card that canrealize high function without increasing the size of an IC chip, andthat can realize cost reduction. Further, it is another object of thepresent invention to provide an IC card that can ensure security bypreventing forgery such as changing a picture of a face, and that candisplay other images as well as a picture of a face.

According to the present invention, a second integrated circuit (thinfilm integrated circuit) formed from a thin semiconductor film ismounted on an IC card as well as an IC chip where a first integratedcircuit is formed. Specifically, a thin film integrated circuit of aboutfrom 1 μm to 5 μm in total film thickness can be formed by using a thinsemiconductor film of 500 nm or less in film thickness. And the thinfilm integrated circuit is transferred on a plastic substratefunctioning as a support medium, and it is electrically connected to anIC chip similarly mounted on the plastic substrate.

Various methods as follows can be employed as a transfer method of athin film integrated circuit: a method of providing a metal oxide filmbetween a favorably heat-resisting substrate and a thin film integratedcircuit, and weakening the metal oxide film by crystallization toseparate the thin film integrated circuit from the favorableheat-resisting substrate and transfer the thin film integrated circuitonto a plastic substrate; a method of providing an amorphous siliconfilm containing hydrogen between a favorably heat-resisting substrateand a thin film integrated circuit and removing the amorphous siliconfilm by laser irradiation or etching to separate the thin filmintegrated circuit from the favorable heat-resisting substrate andtransfer the thin film integrated circuit onto a plastic substrate; amethod of mechanically removing a favorably heat-resisting substrate inwhich a thin film integrated circuit is formed or removing it by etchingwith a solution or a gas to separate the thin film integrated circuitfrom the favorable heat-resisting substrate and transfer the thin filmintegrated circuit onto a plastic substrate; and the like.

Note that an integrated circuit formed on an IC chip can be operatedwith higher frequency and has a smaller variation on characteristics ofa semiconductor element than a thin film integrated circuit. Therefore,it is preferable that a radio frequency (RF) circuit in which anoperation at high frequency is required or an analog circuit which iseasy to be affected by a variation of characteristics of a semiconductorelement is formed in an IC chip. A digital circuit that is less affectedby a variation of characteristics of a semiconductor element than ananalog circuit or a low operation frequency circuit that can operatefavorably with a thin semiconductor element or the like is preferablymounted on an IC card as a thin film integrated circuit. When a memoryhaving a larger capacity is required, a memory may be formed on an ICchip. A memory may be formed as a thin film integrated circuit if thecapacity of a memory can be controlled. As mentioned above, the yield ofthe whole integrated circuit can be increased and cost can be reduced byforming individually a circuit to be mounted as an IC chip and a circuitto be mounted as a thin film integrated circuit depending oncharacteristics of the circuits. A higher function IC card can beobtained while downsizing an IC chip.

In the present invention, a display device thin enough to be fit in anIC card is mounted on an IC card. A semiconductor element used for thedisplay device is formed together with a thin film integrated circuitand transferred onto a plastic substrate. A display element of thedisplay device may be manufactured after transferring, but may bemanufactured before transferring. In the case where a display element ismanufactured after transferring, for example, in the case of a liquidcrystal display device, a pixel electrode of a liquid crystal cell thatis electrically connected to a TFT that is one of semiconductorelements, or an orientation film covering the pixel electrode ismanufactured first and then the display element is transferred. Afterthat, an opposite substrate that has been manufactured separately isattached thereto and a liquid crystal is injected thereinto to completethe display device.

Note that a liquid crystal display device, a light-emitting device inwhich a light-emitting element typified by an organic light-emittingelement is provided for each pixel, a DMD (Digital Micromirror Device),an electronic display and the like can be used as the display device.

Moreover, a thin film integrated circuit that has been formed separatelymay be attached and laminated to increase a circuit scale or a memorycapacity. A thin film integrated circuit is much thinner than an IC chipformed by using a semiconductor substrate, and thus, the mechanicalintensity of an IC card can be maintained to some extent even whenplural thin film integrated circuits are laminated. A connection betweenthe laminated thin film integrated circuits can be made by using a knownconnection method such as a flip chip method, a TAB (Tape AutomatedBonding) method, or a wire bonding method.

Note that a mode of an IC chip is not limited to a mode of mounting itdirectly as a bare chip, but a mode of transferring an IC chip onto aninterposer to be packaged and transferring it, is also possible. As forthe packaging, every known mode such as DIP (Dual In-line Package), QFP(Quad Flat Package), SOP (Small Outline Package) is possible as well asCSP (Chip Size Package) and MCP (Multi Chip Package).

In the present invention, because not only an IC chip but also a thinfilm integrated circuit of 5 μm thick in total, preferably about 2 μm,is mounted on an IC card, a circuit scale or a memory capacity of thewhole integrated circuit can be increased and a higher function IC cardcan be obtained while downsizing an IC chip. The thickness of a displaydevice can be set to about 0.5 mm, preferably, about 0.3 mm.Accordingly, it is possible to provide a display device for an IC cardhaving a thickness of from 0.5 mm through 1.5 mm. A large scaleintegrated circuit is formed by combining a thin film integrated circuitand an IC chip that are each formed separately, and therefore, the yieldcan be more increased than the case of forming integrated circuits onone substrate simultaneously.

These and other objects, features and advantages of the presentinvention become more apparent upon reading of the following detaileddescription along with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1A to 1C show an appearance and internal structures of an IC cardof the present invention;

FIGS. 2A to 2E show an appearance and internal structures of an IC cardof the present invention,

FIGS. 3A and 3B each show a structure of a connection portion of awiring and a terminal in an IC card of the present invention;

FIG. 4 is a block diagram showing a configuration of an IC card of thepresent invention;

FIGS. 5A and 5B are block diagrams each showing a configuration of an ICcard of the present invention;

FIG. 6 is a block diagram showing a configuration of an IC card of thepresent invention;

FIG. 7 is an appearance of an IC card equipped with a solar battery;

FIGS. 8A to 8D are cross-sectional views of an IC card of the presentinvention;

FIGS. 9A to 9C each show a method for manufacturing a semiconductorelement of an IC card of the present invention;

FIGS. 10A and 10B each show a method for manufacturing a semiconductorelement of an IC card of the present invention;

FIGS. 11A and 11B each show a method for manufacturing a semiconductorelement of an IC card of the present invention;

FIGS. 12A and 12B each show a method for manufacturing a semiconductorelement of an IC card of the present invention;

FIGS. 13A and 13B each show a method for manufacturing a semiconductorelement of an IC card of the present invention;

FIGS. 14A to 14D each show a method for manufacturing an IC card using alarge card substrate, according to the present invention;

FIGS. 15A and 15B are cross-sectional views of a liquid crystal displaydevice;

FIG. 16 is a cross-sectional view of a light-emitting device; and

FIG. 17 shows an application mode of an IC card of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment modes of the present invention are described with theaccompanying drawings.

FIG. 1A shows one mode of an IC card according to the present invention.The IC card shown in FIG. 1A is a noncontact type card for sending andreceiving data with a reader/writer of terminal equipment without beingcontacted therewith. Reference numeral 101 shows a card body. Referencenumeral 102 corresponds to a pixel portion of a display device providedfor the card body 101.

A structure of a card substrate 103 included in the card body 101 ofFIG. 1A is shown in FIG. 1B. A thin film integrated circuit 104 formedfrom a thin semiconductor film and a display device 105 are attached tothe card substrate 103. The thin film integrated circuit 104 and thedisplay device 105 are both formed on substrates prepared separately andthen, transferred onto the card substrate 103. In this specification, aportion that is formed by using a thin semiconductor film including thethin film integrated circuit 104 and the display device 105 and thentransferred onto the card substrate 103 is referred to as a thin filmportion 107.

Further, an IC chip 106 using a single crystal semiconductor substrateis mounted on the card substrate 103 and an integrated circuit is formedin the IC chip 106. A way of mounting of the IC chip 106 may be a knownCOG method, wire bonding method or TAB method without being limited inparticular. Note that a first integrated circuit formed on an IC chip isreferred to as a single crystal integrated circuit in this specificationin order to distinguish it from a thin film integrated circuit. The ICchip 106 is electrically connected to the thin film portion 107 througha wiring 108 formed in the card substrate 103.

In addition, an antenna coil 109 connected electrically to the IC chip106 is formed on the card substrate 103. Because sending and receptionof data with a terminal device can be performed by the antenna coil 109without contacting by using electromagnetic induction, a noncontact typeIC card is less damaged by physical abrasion than a contact type ICcard. Moreover, a noncontact type IC card is also used as a tag (awireless tag) for conducting information management without contacting.In a noncontact type IC card, the amount of information that can bemanaged is larger drastically than a barcode that can read informationwithout contacting similarly. Further, it is possible to make thedistance from a terminal device that can read information longer in thecase of using a noncontact type IC card than the case of using abarcode.

Note that FIG. 1B shows the example in which the antenna coil 109 isformed on the card substrate 103, but an antenna coil made separatelymay be mounted on the card substrate 103. For example, a material formedby winding a copper wire in coil like and pressing the copper wire withit sandwiched by two plastic films each having a thickness of about 100μm can be used as an antenna coil. In addition, an antenna coil may beincorporated in a thin film integrated circuit.

In FIG. 1B, one antenna coil 109 is used for one IC card. However, aplurality of antenna coils 109 may be used as shown in FIG. 1C.

Note that a mode of an IC card mounting a display device is shown inFIGS. 1A to 1C, but the present invention is not limited to thisstructure. A display device is not necessarily provided for an IC cardof the present invention. However, it is possible to display data of aphotograph of a human face in a display device and to make replacing thephotograph of a human face more difficult by providing the displaydevice, as compared with the case of using the printing method.Moreover, other information than the photograph of a human face can bedisplayed and a higher function IC card can be obtained.

Various methods as follows can be employed as a transfer method of thethin film portion 107: a method of providing a metal oxide film betweena favorably heat-resisting substrate and the thin film portion 107, andweakening the metal oxide film by crystallization to separate the thinfilm portion 107 from the favorable heat-resisting substrate andtransfer the thin film portion 107 onto the card substrate 103; a methodof providing an amorphous silicon film containing hydrogen between afavorably heat-resisting substrate and the thin film portion 107 andremoving the amorphous silicon film by laser irradiation or etching toseparate the thin film portion 107 from the favorable heat-resistingsubstrate and transfer the thin film portion 107 onto the card substrate103; a method of mechanically removing a favorably heat-resistingsubstrate in which the thin film portion 107 is formed or removing it byetching with a solution or a gas to separate the thin film portion 107from the favorable heat-resisting substrate and transfer the thin filmportion 107 onto the card substrate 103; and the like.

A flexible plastic substrate can be used for the card substrate 103.ARTON manufactured by JSR corporation, which is made of norbornene resinincluding a polar group, can be used for the plastic substrate. Further,a plastic substrate such as polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), polycarbonate (PC),nylon, polyetheretherketone (PEEK), polysulfone (PSF), polyetherimide(PEI), polyarylate (PAR), polybutylene telephthalate (PBT), or polyimidecan be used.

A plastic substrate has a poor heat resistance to a temperature of theheat treatment conducted in the manufacturing process of a semiconductorelement, and thus, it is difficult to use. However, according to thepresent invention, a glass substrate, a silicon wafer or the like havingrelatively high heat resistance up to a temperature in the manufacturingprocess including a heat treatment is used and a semiconductor elementcan be transferred onto a card substrate made of plastic, after themanufacturing process is finished. As a result, a thin film integratedcircuit or a display device is formed on a plastic substrate that isthinner than a glass substrate or the like.

For example, the transferring using a metal oxide film is performedaccording to the following steps.

A first substrate is prepared first, which has a heat-resistance enoughto withstand a heat treatment in manufacturing steps of a semiconductorelement. After forming a metal film on the first substrate, a surface ofthe metal film is oxidized to form an ultrathin metal oxide film withthe thickness of a few nanometers. Next, an insulating film and asemiconductor film are sequentially formed to be laminated on the metaloxide film. The insulating film may have a single layer structure or alaminated structure of multilayer. A silicon nitride, a siliconoxynitride, a silicon oxide and the like can be employed. By using theformed semiconductor film, a semiconductor element used for a thin filmintegrated circuit or a display device is manufactured.

After forming the semiconductor element, a second substrate is attachedso that the semiconductor element is covered by the second substrate andsandwiched between the first and second substrates. It is to be notedthat in the case of forming a display device concurrently with the thinfilm integrated circuit, the second substrate is attached before orafter completing a display element For example, in the case of attachingthe second substrate before completing the display element, for example,when a liquid crystal cell is employed as the display element, a pixelelectrode of the liquid crystal cell that is electrically connected to athin film transistor (TFT) that is one of semiconductor elements, or anorientation film covering the pixel electrode is formed. Thereafter, thesecond substrate is attached before an opposite substrate in which anopposite electrode is formed, is attached.

Subsequently, in order to increase the rigidity of the first substrate,a third substrate is attached to the side opposite to the side of thefirst substrate on which the semiconductor element is formed. By makingthe first substrate more rigid than the second substrate, the firstsubstrate can be separated smoothly with the semiconductor element lessdamaged. It is to be noted that the third substrate is not necessarilyattached when the first substrate has rigidity high enough to withstandthe separation from the semiconductor element.

Subsequently, the metal oxide film is crystallized by a heat treatmentor the like so as to enhance brittleness of the metal oxide film andfacilitate the separation of the first substrate from the semiconductorelement. Then, the first substrate and the third substrate are separatedsimultaneously from the semiconductor element. It is to be noted thatthe heat treatment for crystallizing the metal oxide film may be carriedout either before attaching the third substrate or before attaching thesecond substrate. Alternatively, the heat treatment conducted in thesteps of manufacturing the semiconductor element may serve also as thestep of crystallizing the metal oxide film.

The first substrate and the third substrate are separated together fromthe semiconductor element. Three portion are generated in theseparation: a portion where the metal film is separated from the metaloxide film, a portion where the insulating film is separated from themetal oxide film, and a portion where the metal oxide film itself isseparated into two sides. In either case, the semiconductor element isseparated from the first substrate so as to be attached to the secondsubstrate.

Subsequently, the first substrate is separated from the semiconductorelement that has been attached to the second substrate, and then, thesemiconductor element is attached to the card substrate with an adhesiveagent or the like. Then, the second substrate is separated so as totransfer the semiconductor element onto the card substrate. In thistransferring step, a wiring formed on the card substrate and a thin filmintegrated circuit formed from a semiconductor element may electricallyconnected to each other.

In the case of laminating a thin film integrated circuit, a thin filmintegrated circuit of the next layer is formed on another substrateprepared separately and transferred again so as to be stacked on thethin film integrated circuit that has been transferred earlier. Byrepeating transferring in this manner, thin film integrated circuits canbe stacked on the card substrate. At this time, interlayer insulatingfilms formed of resin or the like may be interposed between each thinfilm integrated circuit. Also, the adhesive agent which is used fortransferring may substitute for the interlayer insulating films.

Note that a thin film integrated circuit and a display device may betransferred simultaneously or may be transferred individually.

FIG. 2A shows one mode of an IC card according to the present invention.The IC card shown in FIG. 2A is a contact type card for sending andreceiving data by electrically connecting a connection terminal providedfor the IC card to a reader/writer of a terminal device.

Reference numeral 201 denotes a card body. Reference numeral 202corresponds to a pixel portion of a display device mounted on the cardbody 201. Reference numeral 203 corresponds to a connection terminal ofa thin film integrated circuit also mounted on the card body 201. Theconnection terminal 203 is a terminal for sending and receiving databetween the terminal device and the IC card by being directly connectedto a reader/writer provided for the terminal device.

A structure of a card substrate 204 included in the card body 201 ofFIG. 2A is shown in FIG. 2B. A thin film integrated circuit 205 formedfrom a thin semiconductor film and a display device 206 are attached tothe card substrate 204 as in FIG. 1B. The thin film integrated circuit205 and the display device 206 are both formed on substrates preparedseparately and then, transferred onto the card substrate 204. In thisspecification, the thin film integrated circuit 205 and the displaydevice 206 correspond to a thin film portion 207. A transfer method ofthe thin film portion 207 is similar to the case of FIG. 1A to 1C.

FIG. 2C shows an enlarged view of the connection terminal 203 shown inFIGS. 2A and 2B. FIG. 2D shows an enlarged view of a backside of FIG. 2Cand it shows the printed wiring board 208 in which the connectionterminal 203 is formed. The connection terminal 203 is formed on theprinted wiring board 208 and is electrically connected to a terminal 210that is formed on the backside of the printed wiring board 208 through acontact hole 209 formed in the printed wiring board 208. FIG. 2C showsan example that eight connection terminals 203 are provided, but thenumber of terminals is not limited thereto, naturally.

An IC chip 211 where a single crystal integrated circuit is formed, isprovided on the backside of the face where the connection terminal 203is formed, in the printed wiring board 208. The IC chip 211 iselectrically connected to the terminal 210. Further, a terminal 212 forelectrically connecting the IC chip 211 to the thin film integratedcircuit is formed on the backside of the face where the connectionterminal 203 is formed, in the printed wiring board 208.

FIG. 2D shows a mode of connecting the IC chip 211 to the terminals 210and 212 by a wire bonding method, but the present invention is notlimited to this. A flip chip method using a solder ball or other methodsmay be employed for the connection in addition to a wire bonding method.

The terminal 212 can be connected to a wiring 213 formed in the cardsubstrate 204 by attaching the backside of the printed wiring board 208to the card substrate 204 as shown in FIG. 2B. The IC chip 211 iselectrically connected to the thin film portion 207 through the wiring213.

FIG. 2E shows a cross sectional view of a mode that the backside of theprinted wiring board 208 is attached to the card substrate 204. As shownin FIG. 2E, the connection terminal 203 is electrically connected to theterminal 210 through the contact hole 209. The IC chip 211 iselectrically connected to the terminals 210 and 212. A mold 214including resin or the like is formed to cover the IC chip 211 and theterminal 210. The terminal 212 is not covered with the mold 214 whollyand at least a part thereof is made exposed from the mold 214. Theterminal 212 is electrically connected to the wiring 213 by anisotropicconductive resin 215.

Because sending and reception of data with a terminal device can beperformed by an electrical connection between the a reader/writer of theterminal device and the connection terminal in the case of a contacttype IC card, electric power is supplied to an IC card more stably andis at less risk for communication failure than a noncontact type ICcard.

Note that, in the present invention, an electric connection between theIC chip and the thin film integrated circuit is not limited to the modesshown in FIGS. 1A to 1C and, FIGS. 2A to 2E. The electrical connectionmay be performed by directly connecting a terminal of the IC chip and aterminal of the thin film integrated circuit with anisotropic conductiveresin, a solder, or the like instead of using a wiring formed on thecard substrate.

The connection between the thin film integrated circuit and the wiringformed on the card substrate may be performed by a wire bonding method,a flip chip method using a solder ball, or it may be performed bydirectly connecting with anisotropic conductive resin or a solder, or byother methods, in FIGS. 1A to 1C and, FIGS. 2A to 2E.

A cross-sectional view in a connection portion between a thin filmintegrated circuit 301 and a wiring 302 formed on a card substrate 303is shown in FIG. 3A. In FIG. 3A, the thin film integrated circuit 301 isattached to the card substrate 303 by an adhesive layer 306. A terminal304 for outputting and inputting a signal or a power supply voltage inthe thin film integrated circuit 301 is connected to the wiring 302formed on the card substrate 303 via anisotropic conductive resin 305.

A cross-sectional view in a connection portion between a thin filmintegrated circuit 311 and a wiring 312 formed on a card substrate 313is shown in FIG. 3B. In FIG. 3B, the thin film integrated circuit 311 isattached to the card substrate 313 by an adhesive layer 316. A terminal314 for outputting and inputting a signal or a power supply voltage inthe thin film integrated circuit 311 is connected to the wiring 312formed on the card substrate 313 via a wire 315.

In FIG. 3A, the thin film integrated circuit 301 is attached so that theterminal 304 faces the card substrate 303 side. In FIG. 3B, the thinfilm integrated circuit 311 is attached so that the terminal 314 facesthe opposite side of the card substrate 313. Therefore, when a displaydevice is transferred onto the card substrate together with the thinfilm integrated circuit, since it is necessary that a side where adisplay element will be formed ultimately or a side where a displayelement is formed faces the opposite side of the card substrate, thedirection of the terminal is determined depending on the direction ofthe display element. When a thin film integrated circuit and a displaydevice are transferred separately, there is an advantage that adirection of a terminal needs not to be limited depending on thedirection of the display element.

One mode of a functional structure of an IC chip and a thin filmintegrated circuit in a noncontact type IC card is describedhereinafter. FIG. 4 shows a block diagram of the noncontact type ICcard.

Reference numeral 400 denotes an input antenna coil, 401 denotes anoutput antenna coil. 402 denotes an input interface, and 403 denotes anoutput interface. It is noted that the number of each antenna coil isnot limited to the number shown in FIG. 4. AC power supply voltage orvarious signals inputted from a terminal device by the input antennacoil 400 are demodulated or made a direct current in the input interface402, and then supplied to various circuits such as a CPU 404, a ROM 405,a RAM 406, an EEPROM 407, a coprocessor 408, and a controller 409. Thesignal that is processed or generated in each of the circuits ismodulated in the output interface 403, and sent to the terminal deviceby the output antenna coil 401.

It should be noted that various circuits shown in FIG. 4 is mere onemode of the present invention, and thus, various circuits to be mountedon an IC card are not limited to the above described circuits.

All processes of the IC card are controlled by the CPU 404 in FIG. 4.Each program used in the CPU 404 is memorized in the ROM 405. Thecoprocessor 408 is a secondary coprocessor for helping the main CPU 404to operate. The RAM 406 is used as an operation area during dataprocessing as well as a buffer during a communication with a terminaldevice. The EEPROM 407 can memorize data inputted as a signal in adetermined address.

Note that, image data such as a photograph of a face is memorized in theEEPROM 407 when the data can be rewritten, and in the ROM 405 when thedata cannot be rewritten. Alternatively, another memory for memorizingimage data may be provided.

A signal including image data is exposed to data processing inaccordance with a specification of the display device 410 and suppliedto the display device 410 as a video signal by the controller 409. Inaddition, an Hsync signal, a Vsync signal, a clock signal CLK, and analternating voltage (AC Cont), etc. are generated based on respectivesignals or power supply voltage inputted from the input interface 402and are supplied to the display device 410 by the controller 409.

A pixel portion 411 in which a display element is provided for eachpixel, a scanning line driver circuit 412 for selecting a pixel providedfor the pixel portion 411, and a signal line driver circuit 413 forsupplying a video signal to the selected pixel are formed in the displaydevice 410. Note that, reference numeral 427 denotes a thin film portionwhich includes the thin film integrated circuit 426 and the displaydevice 410.

FIG. 5A shows a more detailed structure of the input interface 402. Arectification circuit 420 and a demodulation circuit 421 are provided inthe input interface 402 shown in FIG. 5A. AC power supply voltageinputted from the input antenna coil 400 is rectified in therectification circuit 420 and supplied to each circuit as DC powersupply voltage. Each of AC signals inputted from the input antenna coil400 is demodulated in the demodulation circuit 421, and various signalswaveform-shaped by demodulation are supplied to each circuit.

FIG. 5B shows a more detailed structure of the output interface 403. Amodulation circuit 423 and an amplifier 424 are provided in the outputinterface 403 shown in FIG. 5B. Various signals that are inputted to theoutput interface 403 from each circuit are modulated in the modulationcircuit 423, amplified or buffer-amplified in the amplifier 424, andthen, sent to the terminal device from the output antenna coil 401.

In FIG. 4, an example of a noncontact type IC card using a coil antennais shown. However, the noncontact type IC card is not limited thereto. Alight emitting element, an optical sensor or the like may be used forsending and receiving data.

Note that an integrated circuit formed on an IC chip can be operatedwith higher frequency and has a smaller variation on characteristics ofa semiconductor element than a thin film integrated circuit. Therefore,it is preferable that a radio frequency (RF) circuit in which anoperation at high frequency is required or an analog circuit which iseasy to be affected by a variation of characteristics of a semiconductorelement is formed in an IC chip. A digital circuit that is less affectedby a variation of characteristics of a semiconductor element than ananalog circuit or a low operation frequency circuit that can operatefavorably with a thin semiconductor element or the like is preferablymounted on an IC card as a thin film integrated circuit.

For example, in FIG. 5, the input interface 402 and the output interface403 including analog circuits such as the rectification circuit 420, thedemodulation circuit 421, and the modulation circuit 423 are formed inan IC chip 425. Various circuits such as the CPU 404, the ROM 405, theRAM 406, the EEPROM 407, the coprocessor 408, and the controller 409 areformed from the thin film integrated circuit 426.

When a memory having a larger capacity is required, either or all of theROM 405, the RAM 406 and EEPROM 407 may be formed from the IC chip 425.

The structures of the IC chip 425, the thin film integrated circuit 426and the display device 410 shown in FIG. 4 are only examples, and thepresent invention is not limited thereto. For example, a function suchas GPS may be provided. The display device 410 may have a function ofdisplaying an image, and it may be active type or passive type.

Next, one mode of functional structures of an IC chip and a thin filmintegrated circuit in a contact type IC card is described. FIG. 6 showsa block diagram of the contact type IC card.

Reference numeral 430 denotes a connection terminal, and 431 denotes aninterface. It is noted that the number of the connection terminals 430is not limited to the number shown in FIG. 6. A power supply voltage orvarious signals inputted from the connection terminal 430 isbuffer-amplified in the interface 431, and then supplied to variouscircuits such as a CPU 434, a ROM 435, a RAM 436, an EEPROM 437, acoprocessor 438, and a controller 439. Various signals that areprocessed or generated in the circuits are buffer-amplified in theinterface 431, and sent to the terminal device. A pixel portion 441where a display element is provided for each pixel, a scanning linedriver circuit 442 for selecting a pixel provided in the pixel portion441, and a signal line driver circuit 443 for supplying a video signalto the selected pixel are provided in the a display device 440.

It should be noted that various circuits shown in FIG. 6 is mere onemode of the present invention, and thus, various circuits to be mountedon an IC card are not limited to the above described circuits.

For example, in FIG. 6, the interface 431 is formed in an IC chip 445.Various circuits such as the CPU 434, the ROM 435, the RAM 436, theEEPROM 437, the coprocessor 438, and the controller 439 are formed froma thin film integrated circuit 446. When a memory having a largercapacity is required, either or all of the ROM 435, the RAM 436 andEEPROM 437 may be formed from the IC chip 445.

The structures of the IC chip 445, the thin film integrated circuit 446and the display device 440 shown in FIG. 6 are only examples, and thepresent invention is not limited thereto. For example, a function suchas GPS may be provided. The display device 440 may have a function ofdisplaying an image, and it may be active type or passive type.

As mentioned above, the yield of the whole integrated circuit can beincreased and cost can be reduced by forming individually a circuit tobe mounted as an IC chip and a circuit to be mounted as a thin filmintegrated circuit depending on characteristics of the circuits. Ahigher function IC card can be obtained while downsizing an IC chip.

Further, FIG. 4 and FIG. 6 each show an example of supplying a powersupply voltage from a reader/writer of a terminal device. However, thepresent invention is not limited thereto. For example, as shown in FIG.7, a solar battery 1502 may be provided in an IC card. An ultrathin typebattery such as a lithium battery may be incorporated.

Then, a shape of the card substrate is described.

One mode of a cross-sectional structure of a noncontact type IC card isshown in FIG. 8A. Reference numeral 801 denotes a card substrate in FIG.8A, and a concave portion 803 is formed. An IC chip 802 is mounted onthe card substrate 801 in the concave portion 803. Reference numeral 805denotes a thin film portion that includes a thin film integrated circuit806 and a display device 807. The thin film integrated circuit 806 iselectrically connected to the IC chip 802 by a wiring 808 formed on thecard substrate 801.

A covering material 810 is attached to face the card substrate 801 withthe IC chip 802, the thin film integrated circuit 806 and the antennacoil 804 therebetween by an adhesive agent 811. In FIG. 8A, an openingportion 812 is provided in a portion of the covering material 810 andthe covering material 810 is attached so that the display device 807 islocated in the opening portion 812. However, the opening portion 812 isnot necessarily provided in the portion of the covering material 810 inthe present invention. For instance, a material that can transmit lightthrough a portion overlapping with the display device 807, may be usedas the covering material 810.

Reference numeral 804 denotes an antenna coil. FIG. 8A shows an exampleof forming the antenna coil 804 on the card substrate 801, but anantenna coil formed separately may be mounted on the card substrate 801.Further, FIG. 8A shows an example of the antenna coil 804 providedoutside the concave portion 803 of the card substrate 801, but theantenna coil 804 may be provided in the concave portion 803.

Note that the card substrate has the concave portion for providing an ICchip therein, in the IC card shown in FIG. 8A, but the concave portionmay be provided in the covering material. FIG. 8B shows across-sectional view of a noncontact type IC card when a concave portionis provided in a covering material.

In FIG. 8B, an IC chip 821 and a thin film portion 815 are formed on aflat card substrate 819. The thin film portion 815 includes a thin filmintegrated circuit 816 and a display device 817. The card substrate 819and a covering material 814 are attached to each other with the IC chip821 and the thin film portion 815 therebetween. The covering material814 includes concave portions 820 and 818 on the card substrate 819side, and the concave portions 820 and 818 are overlapped with the ICchip 821 and the display device 817, respectively.

A material that can transmit light in the concave portion 818 is used asthe covering material 814.

FIG. 8C shows a cross-sectional view of a noncontact type IC card whenan opening portion is provided in a portion of a covering materialoverlapping with a display device.

In FIG. 8C, an IC chip 861 and a thin film portion 855 are formed on aflat card substrate 859. The thin film portion 855 includes a thin filmintegrated circuit 856 and a display device 857. The card substrate 859and the covering material 854 are attached to each other with the ICchip 861 and the thin film portion 855 therebetween. The coveringmaterial 854 includes concave portions 860 and 862 and an openingportion 858 on the card substrate 859 side. The concave portion 860 isoverlapped with the IC chip 861, and the concave portion 862 and theopening portion 858 are overlapped with the display device 857. Asubstrate covering a display element of the display device 857 has aconcave portion and the concave portion is engaged and overlapped withthe opening portion 858.

FIG. 8D shows one mode of a cross-sectional structure of a contact typeIC card. In FIG. 8D, reference numeral 831 denotes a card substrate anda concave portion 833 is formed therein. An IC chip 832 is mounted onthe card substrate 831 in the concave portion 833. Reference numeral 835denotes a thin film portion that includes a thin film integrated circuit836 and a display device 837. The thin film integrated circuit 836 andthe IC chip 832 are electrically connected to each other by a wiring 838formed on the card substrate 831.

A covering material 840 is attached to face the card substrate 831 by anadhesive agent 841 with the thin film integrated circuit 836therebetween. In FIG. 8D, an opening portion 842 is provided in aportion of the covering material 840 and the covering material 840 isattached such that a printed wiring board 843 provided with the IC chip832 is located in the opening portion 842. A connection terminal 844 isformed on the side opposite to the side where the IC chip 832 is formed.The connection terminal 844 is exposed in the opening portion 842 in asurface of the IC card.

FIGS. 8A to 8D each show the modes of forming the IC card by attachingthe covering material to the card substrate where the IC chip or thethin film integrated circuit is formed, but the IC card of the presentinvention is not limited to the modes. For example, an IC card may beformed by sealing a card substrate with resin or the like withoutproviding a covering material, or an IC card may be formed by sealing acard substrate with resin or the like with a covering material provided.

Note that in the case of sealing with resin, a material that cantransmit light may be used for a portion overlapping with a displaydevice, or the portion overlapping with a display device may be exposedwithout being sealed with resin. Note that a connection terminal iscertainly exposed outside of an IC card in the case of sealing withresin.

EMBODIMENT 1

A method for manufacturing a thin film integrated circuit and a displaydevice is described. Note that, in this embodiment, although a TFT isgiven as an example of a semiconductor element, the semiconductorelement included in the thin film integrated circuit and the displaydevice is not limited thereto, and various circuit elements can be used.For example, a memory element, a diode, a photoelectric transferringelement, a resistor element, a coil, a capacitor element, an inductorand the like can be given as a representative example in addition to aTFT.

As shown in FIG. 9A, a metal film 501 is formed on a first substrate 500by sputtering. The metal film 501 is made of tungsten to be from 10 nmto 200 nm, preferably from 50 nm to 75 nm in thickness. In thisembodiment, the metal film 501 is formed directly on the first substrate500. However, the first substrate 500 may be covered with an insulatingfilm such as a silicon oxide, a silicon nitride, a silicon oxynitrideand then, the metal film 501 may be formed thereover.

After the metal film 501 is formed, an oxide film 502 to serve as aninsulating film is formed to be laminated without being exposed to theair. A silicon oxide film is formed to be from 150 nm to 300 nm inthickness as the oxide film 502. When the sputtering method is employed,an edge face of the first substrate 500 is also deposited. Therefore, itis preferable that the metal film 501 and the oxide film 502 depositedon the edge face are selectively removed by O₂ ashing or the like inorder to prevent the oxide film 502 from remaining on the side of thefirst substrate 500 in a later step of separating.

When the oxide film 502 is formed, a pre-sputtering is performed as thepreliminary step of the sputtering, in which plasma is generated whileblocking off between a target and the substrate with a shutter. Thispre-sputtering step is performed under the condition that the flow ratesof Ar and O₂ are set to 10 sccm and 30 sccm, respectively, thetemperature of the first substrate 500 is set to 270° C., and depositionpower is set to 3 kW until the plasma reaches a stable state.Subsequently, an ultrathin metal oxide film 503 of about several nm(here, 3 nm) is formed between the metal film 501 and the oxide film 502by the sputtering. The surface of the metal film 501 is oxidized to formthe metal oxide film 503. Accordingly, the metal oxide film 503 is madeof tungsten oxide in this embodiment.

In this embodiment, the metal oxide film 503 is formed by thesputtering. However, the present invention is not limited to the method.For example, the metal oxide film 503 may be formed by oxidizingdeliberately the surface of the metal film 501 by plasma in theatmosphere of oxygen or oxygen added with inert gases such as Ar.

After forming the oxide film 502, a base film 504 is formed by PCVD.Here, a silicon oxynitride film is formed to have a thickness ofapproximately 100 nm as the base film 504. After forming the base film504, a semiconductor film 505 is formed without being exposed to theair. The semiconductor film 505 is formed to have a thickness of from 25nm to 100 nm, preferably, from 30 nm to 60 nm. The semiconductor film505 may be an amorphous semiconductor, a microcrystalline semiconductor(semiamorphous semiconductor) or a polycrystalline semiconductor.Silicon germanium as well as silicon may be used for the semiconductor.In the case of using silicon germanium, the concentration thereof ispreferably approximately from 0.01 to 4.5 atomic %.

The semiconductor film 505 is crystallized by a known technique. Asknown methods of crystallization, there are a thermo-crystallizationmethod using an electrically heated oven, a laser crystallization methodusing laser light, and a lamp annealing crystallization method using aninfrared ray. Alternatively, a crystallization method using a catalystelement may be employed according to the technique described in JapanesePatent Laid Open No. H07-130652.

In this embodiment, the semiconductor film 505 is crystallized by lasercrystallization. Before the laser crystallization, thermal annealing isperformed on the semiconductor film 505 for an hour at 500° C. toenhance the resistance of the semiconductor film to laser light. In thisembodiment, brittleness of the metal oxide film 503 is enhanced by theheat treatment, and thus, the first substrate 500 is separated moreeasily later. The metal oxide film 503 is easily cracked by thecrystallization in the grain boundary to enhance the brittlenessthereof. In this embodiment, the crystallization of the metal oxide film503 is preferably performed for from 0.5 to 5 hours at temperatures from420° C. to 550° C.

It is possible to obtain crystals having a large grain size byirradiating a laser light of second to fourth harmonics with respect toa fundamental harmonic with a solid-state laser that is capable ofcontinuously emitting. Typically, it is preferable to use secondharmonic (532 nm) or third harmonic (355 nm) of an Nd:YVO₄ laser(fundamental harmonic: 1064 nm). Specifically, laser light emitted froma continuous wave type YVO₄ laser is converted to the harmonic with anon-linear optical element to obtain laser light with the output powerof 10 W. Further, there is a method of obtaining a harmonic by using anon-linear optical element. Preferably, the laser light is formed so asto have a rectangular shape or an elliptical shape on an irradiatedsurface by using an optical system, and then irradiated to thesemiconductor film 505. On this occasion, an energy density ofapproximately from 0.01 MW/cm² to 100 MW/cm² (preferably from 0.1 MW/cm²to 10 MW/cm²) is necessary. The scanning speed thereof is set toapproximately from 10 cm/s to 2000 cm/s to irradiate laser light.

The laser crystallization may be conducted by irradiating continuouswave laser light of a fundamental wave and continuous wave laser lightof a harmonic, or irradiating continuous wave laser light of afundamental wave and pulsed laser light of a harmonic.

Laser light may be irradiated in the inert gas atmosphere such as noblegas or nitride. According to this, the surface roughness of asemiconductor due to laser irradiation, and further, fluctuation on athreshold value due to the variations of interface state density can besuppressed.

The degree of crystallinity of the semiconductor film 505 is enhanced bythe above described laser irradiation on the semiconductor film 505. Thesemiconductor film 505 that is a polycrystalline semiconductor film mayin advance be formed by a sputtering method, a plasma CVD method, athermal CVD method, or the like.

The semiconductor film is crystallized in this embodiment, but anamorphous silicon film may be used in the next process withoutperforming the crystallization.

Then, as shown in FIG. 9B, the semiconductor film 505 is patterned toform island-like semiconductor films 507 and 508. Various semiconductorelements as typified by a TFT are formed using the island-likesemiconductor films 507 and 508. In this embodiment, the island-likesemiconductor films 507 and 508 are in contact with the base film 504,but an electrode, an insulating film, or the like may be formed betweenthe base film 504 and the island-like semiconductor films 507 and 508,in some semiconductor elements. For example, in the case of a bottomgate TFT that is one of the semiconductor elements, a gate electrode anda gate insulating film are formed between the base film 504 and theisland-like semiconductor films 507 and 508.

In this embodiment, top gate TFTs 509 and 510 are formed using theisland-like semiconductor films 507 and 508 (FIG. 9C). Specifically, agate insulating film 511 is formed so as to cover the island-likesemiconductor films 507 and 508. Then, a conductive film is formed overthe gate insulating film 511 and patterned to form gate electrodes 512and 513. Next, impurities imparting n-type are added to the island-likesemiconductor films 507 and 508 by using the gate electrodes 512 and 513or resist that is formed and patterned as a mask to form a sourceregion, a drain region, an LDD (Lightly Doped Drain) region and thelike. Here, both TFTs 509 and 510 are n-type, but impurities impartingp-type are added in the case of using a p-type TFT.

According to the above-described process, TFTs 509 and 510 can beformed.

A first interlayer insulating film 514 is formed so as to cover the TFTs509 and 510. Contact holes are provided for the gate insulating film 511and the first interlayer insulating film 514, and then, wirings 515 to518 connected to the TFTs 509 and 510 through the contact holes areformed to be in contact with the first interlayer insulating film 514.

A second interlayer insulating film 519 is formed over the firstinterlayer insulating film 514 so as to cover the wirings 515 to 518(FIG. 10A). Contact holes are formed in the second interlayer insulatingfilm 519, and wirings 520 and 521 to connect to the wirings 515 and 518through the contact holes and a wiring 522 to serve as a terminal areformed to be in contact with the second interlayer insulating film 519.A portion of the wiring 521 serves also as a pixel electrode of a liquidcrystal cell to be formed later. Note that an organic resin, aninorganic insulating film, an insulating film including Si—O bond andSi—CHx bond that are formed by using a siloxane material as a startmaterial, or the like can be used as the first interlayer insulatingfilm 514 and the second interlayer insulating film 519. The insulatingfilm formed by using a siloxane material as a start material iseffective for wire-bonding, since it has heat-resistance enough toresist a contact with a wiring made of a material having a high meltingpoint, such as gold.

As shown in FIG. 10B, a spacer 523 is formed by using an insulatingfilm. An orientation film 524 is formed to cover the wiring 521 and thespacer 523 and exposed to a rubbing treatment.

A protective layer 531 is formed over the second interlayer insulatingfilm 519 to cover the wirings 520 to 522, the spacer 523 and theorientation film 524 as shown in FIG. 11A. A material which can protecta thin film integrated circuit and a display device in bonding orseparating a second substrate 533 later and which can be removed afterseparating the second substrate 533, is used as the protective layer531. For example, the protective layer 531 can be formed by coating anepoxy, acrylate, or silicone resin that is soluble in water or alcohol,over the whole surface.

In this embodiment, water-soluble resin (manufactured by TOAGOSEI Co.,Ltd.: VL-WSHL10) is spin-coated to have a thickness of 30 μm, andexposed for two minutes to be tentatively cured. After that, it isexposed its back to UV rays for 2.5 minutes, and then, exposed itssurface for 10 minutes, namely 12.5 minutes to be fully cured in total.Consequently, the protective layer 531 is formed.

In the case of stacking a plurality of organic resin, there is a risk ofmelting partially the stacked organic resin depending on the usedsolvent during coating or baking, or increasing the adhesion thereofexcessively. Therefore, in the case of using organic resins that aresoluble in the same solvent for the second interlayer insulating film519 and the protective layer 531, an inorganic insulating film (aSiN_(X) film, a SiN_(X)O_(Y) film, an AlN_(X) film, or an AlN_(X)O_(Y)film) is preferably formed to cover the second interlayer insulatingfilm 519 so as to remove smoothly the protective layer 531 in a laterstep.

Then, a treatment is carried out in order to partially reduce theadhesion between the metal oxide film 503 and the oxide film 502 or theadhesion between the metal oxide film 503 and the metal film 501,thereby providing a trigger for separation. Specifically, a part of theinside or a part of the vicinity of the interface of the oxide film 503is damaged by pressuring locally from outside along with the peripheryof a region to be separated. In this embodiment, a hard needle such as adiamond pen may perpendicularly be pressed on the periphery of the edgeportion of the metal oxide film 503 and moved along the metal oxide film503 with applying loading. Preferably, a scriber device can be used tomove the pen with applying loading with press force ranging from 0.1 mmto 2 mm. As described above, a portion having reduced adhesion that canspark the start of separation is formed before separating, therebypreventing poor separation in a later separation step and improving theyield.

Next, a second substrate 533 is attached to the protective layer 531with a two-sided tape 532, and a third substrate 535 is pasted over thefirst substrate 500 with a twp-sided tape 534. An adhesive agent may beused instead of the two-sided tape. For example, it is possible toreduce the load that is applied to the semiconductor element inseparating the second substrate 533 by using an adhesive agent that isseparated by UV light. The third substrate 535 is attached to preventthe destruction of the first substrate 500 in a later separation step. Asubstrate that has higher rigidity than that of the first substrate 500,for example, a quartz substrate or a semiconductor substrate ispreferably to be used for the second substrate 533 and the thirdsubstrate 535.

Then, the metal film 501 is separated from the oxide film 502 by aphysical means. The separation of the metal film 501 is started from theregion in which the adhesion of the metal oxide film 503 to the metalfilm 501 or the oxide film 502 is partly reduced in the previousprocess.

Three separating portions result from the separation, that is, a portionin which the metal film 501 is separated from metal oxide film 503, aportion in which the oxide film 502 is separated from the metal oxidefilm 503, and a portion in which the metal oxide film 503 is itselfseparated to two sides. Further, the second substrate 533 to which thesemiconductor elements (here, TFTs 509 and 510) are attached isseparated from the third substrate 535 to which the first substrate 500and the metal film 501 are attached. The separation can be carried outwith comparatively small force (for example, man's hand, air pressure ofgas sprayed from a nozzle, ultrasonic waves, or the like). FIG. 11Bshows a state after the separation step.

A card substrate 540 is bonded to the oxide film 502 to a part of whichthe metal oxide film 503 is attached with an adhesive agent 539 (FIG.12A). In the adhesive bonding, it is important to select a material forthe adhesive agent 539 so that adhesion degree between the oxide film502 and the card substrate 540 by the adhesive agent 539 is higher thanthat between the second substrate 533 and the protective layer 531 bythe two-sided tape 532.

As the adhesive agent 539, various curing adhesive agents, for example,a reaction-curing adhesive agent, a thermal-curing adhesive agent, aphoto-curing adhesive agent such as a UV curing adhesive agent, and ananaerobic adhesive agent can be used. The adhesive agent 539 preferablyhas high thermal conductivity by containing powder comprising silver,nickel, aluminum, or aluminum nitride, or filler.

Note that, in some cases, the adhesion with the card substrate 540becomes worse when the metal oxide film 503 is left in a surface of theoxide film 502. Thus, the metal oxide film 503 may be removedcompletely, and then, the oxide film 502 is bonded to the card substrateto enhance the adhesion.

As shown in FIG. 12B, the two-sided tape 532 and the second substrate533 are separated sequentially or simultaneously from the protectivelayer 531, and then the protective layer 531 is removed. Thus, theprotective layer 531 is removed by water since the protective layer 531is formed of the resin that is soluble in water. In the case where theleft protective layer 531 causes deterioration, a left part of theprotective layer 531 is preferably removed by carrying out a cleaningtreatment or an O₂ plasma treatment on the surface after the removingstep.

Then, a sealing material 550 is formed to seal a liquid crystal in. Asshown in FIG. 13A, a liquid crystal 551 are dropped into the areasurrounded by the sealing material 550. An opposite substrate 552 formedseparately is attached by the sealing material 550. A filler may bemixed into the sealing material. The opposite substrate 552 has athickness of about several hundred μm, and an opposite electrode 553made of a transparent conductive film and an orientation film 554exposed to a rubbing treatment are formed over the opposite substrate552. Further, in addition to them, a color filter or a shielding filmfor preventing disclination may be provided for the opposite substrate.A polarization plate 555 is attached to the opposite side of the facewhere the opposite electrode 553 is formed in the opposite substrate552.

FIG. 13B shows a mode after the opposite substrate 552 is attached. Aportion in which the opposite electrode 553, the liquid crystal 551, andthe wiring 521 are overlapped with one another corresponds to a liquidcrystal cell 556. The liquid crystal cell 556 is completed, and thus,the display device 557 is also completed. In this embodiment, theopposite substrate 552 is not overlapped with the thin film integratedcircuit 558. However, the opposite substrate 552 may be allowed to beoverlapped with the thin film integrated circuit 558. In this case,resin having an insulating property may be filled between the oppositesubstrate and the thin film integrated circuit for the sake of enhancingthe mechanical strength of the IC card.

A liquid crystal is sealed in by a dispenser method (a dripping method)in this embodiment. The present invention, however, is not limited tothe method. A dip method (pumping up method) by which a liquid crystalis sealed in using capillary phenomenon after attaching the oppositesubstrate may be employed.

When the mode shown in FIG. 13B is completed, an IC card is completed byattaching a covering material or sealing with resin after an IC chip ismounted. Note that a connection with the IC chip can be performed by thewiring 522.

Materials used generally can be used for sealing the IC card, forexample, a high-polymer material such as polyester, acrylic acid,polyvinyl acetate, propylene, chloroethylene,acrylonitrile-butadiene-styrene resin, or polyethylene terephthalate canbe used. When the sealing is performed, a pixel portion of the displaydevice is exposed. In the case of a contact-type IC card, a connectionterminal as well as the pixel portion is exposed. The IC card having anappearance shown in FIG. 1A or FIG. 2A can be formed by the sealing.

Sealing with the sealant offers some advantages of enhancing mechanicalstrength of the IC card, radiating heat generated in the thin filmintegrated circuit and the display device, and shielding electromagneticnoises from circuits adjacent to the IC card.

A plastic substrate can be used for the card substrate 540, the oppositesubstrate 552 or the covering material. ARTON manufactured by JSRcorporation, which is made of norbornene resin including a polar group,can be used for the plastic substrate. Polyethylene terephthalate (PET),polyether sulfone (PES), polyethylene naphthalate (PEN), polycarbonate(PC), nylon, polyetheretherketone (PEEK), polysulfone (PSF),polyetherimide (PEI), polyarylate (PAR), polybutylene telephthalate(PBT), polyimide and the like can be used as the plastic substrate. Thecard substrate 540 preferably has high thermal conductivity ofapproximately from 2 W/mK to 30 W/mK for radiating heat generated in thethin film integrated circuit or the display device.

In this embodiment, tungsten is used for the metal film 501, however,the metal film of the present invention is not limited to tungsten. Anymaterial can be used as long as the material includes a metal thatallows a substrate to be separated by forming the metal oxide film 503over the surface of the material and crystallizing the metal oxide film503. For example, TiN, WN, Mo and the like can be used. When an alloy ofthe elements is used as the metal film, the optimum temperature for aheat treatment in crystallization is different depending on thecomposition ratio thereof. Accordingly, a heat treatment can beperformed at a temperature that is not interference in the step ofmanufacturing a semiconductor element by adjusting the compositionratio, and therefore, there are few limitations on choices for theprocess for a semiconductor element.

In laser crystallization, each thin film integrated circuit is formed ina region which fits within a width in a direction perpendicular to thescanning direction of a beam spot of a laser beam, thereby preventingthe thin film integrated circuits from forming in regions having poorcrystallinity (edges) at both ends of the longitudinal axis of the beamspot. According to this, a semiconductor film having few crystal grainboundaries can be used for a semiconductor element in the thin filmintegrated circuit.

According to the above-described method for manufacturing, an ultrathinfilm integrated circuit having a total thickness of from 1 μm through 5μm, typically, about 2 μm can be formed. The thickness of a displaydevice can be set to about 0.5 mm, preferably, about 0.3 mm.Accordingly, it is possible to mount the display device on an IC cardhaving a thickness of from 0.05 mm through 1.5 mm. The thickness of thethin film integrated circuit includes a thickness of an insulating filmprovided between the metal oxide film and the semiconductor element, anda thickness of an interlayer insulating film covering the formedsemiconductor element, in addition to the thickness of the semiconductorelement itself.

The liquid crystal display device described in this embodiment isreflective type. As long as a backlight can be provided for the liquiddisplay device, it may be a transmissive type. When the reflectiveliquid crystal display device is used, it is possible to reduce powerconsumption required for displaying an image more, as compared with atransmissive one. However, when the transmissive liquid crystal displaydevice is used, an image can be seen more easily in the dark, ascompared with the reflective one.

The display device of the present invention is required to have aresolution high enough that a person can be recognized with a photographof the person's face. Therefore, for the sake of using the displaydevice instead of an identification photograph, a resolution of at leastQVGA (320×240) is required.

A semiconductor film, an insulating film or the like used in a displaydevice is incused with a serial number. If a third person gets illegallyan stolen IC card in which image data is not memorized in a ROM, it ispossible to trace the distribution route by the serial number to someextent. In this case, it is efficient to incuse a serial number in apart in which the serial number can be deleted, only when the displaydevice is tore down irreparably and cannot be repaired.

EMBODIMENT 2

Next, an example of manufacturing a plurality of IC cards using alarge-size substrate is described. FIG. 14A shows a state in which adisplay device, an antenna coil, and a thin film integrated circuitcorresponding to a plurality of IC cards are formed over a large-sizecard substrate 601. FIG. 14A shows a state before a covering material isbonded by resin after a protective layer is removed. A region 602surrounded by a dotted line corresponds to one IC card. In the case ofusing a liquid crystal display device as a display device, a liquidcrystal may be injected by a dispenser method or a dip method. However,the dispenser method is employed when an injection port for a liquidcrystal for the dip method cannot be arranged in an edge portion of acard substrate, as shown in FIG. 14A.

An IC chip 606 corresponding to each IC card is mounted, as shown inFIG. 14B.

Resin 603 is applied to cover the IC chip 606, the thin film integratedcircuit, the display device, and the antenna coil corresponding to eachof IC cards, as shown in FIG. 14C. In FIG. 14B, regions to be appliedwith the light-transmitting resin 603 are each separated to correspondto each IC card. However, the resin may be applied to the whole area.When the resin 603 is less light-transmitting, the resin 603 is appliedto a portion that is not overlapped with the display device.

Then, a covering material 604 is attached. The covering material 604 hasan opening portion in a portion overlapping with the display device.

After the covering material 604 is attached, dicing is performed along adotted line 605 to separate the IC cards from one another, as shown inFIG. 14D. The IC card may be complete at this stage, and also may becomplete by sealing with a sealant thereafter. Note that dicing may beperformed by using laser light.

EMBODIMENT 3

A liquid crystal material suitable for the case where a liquid crystaldisplay device is used as a display device and the case where a displayelement is transferred after completed, is described in this embodiment.

FIGS. 15A and 15B are cross sectional views of a liquid crystal displaydevice of this embodiment. A columnar spacer 1401 is provided for apixel in a liquid crystal display device shown in FIG. 15A. The adhesionbetween an opposite substrate 1402 and a substrate 1403 on the side ofelements is enhanced by the columnar spacer 1401. This makes it possibleto prevent a semiconductor element in the outside of the areaoverlapping with a sealing material from remaining on the side of thefirst substrate, when the first substrate is separated.

FIG. 15B is a cross sectional view of a liquid crystal display deviceusing a nematic liquid crystal, a smectic liquid crystal, aferroelectric liquid crystal, or a PDLC (polymer dispersed liquidcrystal) containing these liquid crystals in polymer resin. The adhesionbetween the opposite substrate 1402 and the substrate 1403 on the sideof elements is enhanced by using the PDLC 1404. This makes it possibleto prevent a semiconductor element in the outside of the areaoverlapping with a sealing material from remaining on the side of thefirst substrate, when the first substrate is separated.

Note that a liquid crystal used for the liquid crystal display device ofthe present invention is not limited to the material that is shown inthis embodiment. For example, a PSFLC (a polymer stabilizedferroelectric liquid crystal) may be employed. In this case, after amonomer for forming a PSFLC is injected, the monomer is polymerized byultraviolet ray irradiation, thereby forming the PSFLC. Since the PSFLCcan enhance the adhesion between the opposite substrate and thesubstrate on the side of elements, it can prevent a semiconductorelement in the outside of the area overlapping with a sealing materialfrom remaining on the side of the first substrate, when the firstsubstrate is separated.

EMBODIMENT 4

In this embodiment, a structure of a light-emitting device mounted onthe IC card of the present invention is described.

In FIG. 16, a base film 6001 is formed over a card substrate 6000. Atransistor 6002 is formed on the base film 6001. The transistor 6002 iscovered with a first interlayer insulating film 6006. A secondinterlayer insulating film 6007 and a third interlayer insulating film6008 are laminated over the first interlayer insulating film 6006.

The first interlayer insulating film 6006 is formed by depositing asilicon oxide film, a silicon nitride film, or a silicon oxynitride filmin a single layer or a laminate by a plasma CVD method or a sputteringmethod. An oxynitride film in which mole fraction of oxygen is higherthan that of nitrogen is laminated over an oxynitride film in which molefraction of nitrogen is higher than that of oxygen to form a film. Thefilm may be used as the first interlayer insulating film 6006.

A heat treatment (for 1 to 12 hours at temperatures from 300° C. to 550°C.) is performed after the first interlayer insulating film 6006 isformed. As a result, a dangling bond of a semiconductor contained in anactive layer 6003 can be terminated (hydrogenated) by hydrogen containedin the first interlayer insulating film 6006.

An organic resin film, an inorganic insulating film, an insulating filmincluding Si—O bond and Si—CHx bond that are formed by using a siloxanematerial as a start material, or the like can be used as the secondinterlayer insulating film 6007. A nonphotosensitive acrylic resin isused in this embodiment. A film that prevents more a material such asmoisture or oxygen that is a cause of deterioration of a light emittingelement from penetrating than other insulating films is used for a thirdinterlayer insulating film 6008. Typically, a DLC (diamond like carbon)film, a carbon nitride film, a silicon nitride film formed by a RFsputtering method, or the like is preferably used.

CuPc of 20 nm thick as a hole injection layer 6011, α-NPD of 40 nm thickas a hole transporting layer 6012, Alq₃ of 37.5 nm thick added with DMQdas a light emitting layer 6013, Alq₃ of 37.5 nm thick as an electrontransporting layer 6014, CaF₂ of 1 nm thick as an electron injectionlayer 6015, and Al of from 10 nm to 30 nm thick as a cathode 6016 arelaminated sequentially over an anode 6010 formed from TiN to form alight-emitting element 6019. In FIG. 16, a material that cannot transmitlight is used for the anode 6010, and the cathode 6016 has a thicknessof from 10 nm to 30 nm to transmit light, thereby obtaining lightemitted from the light emitting element 6019 from the side of thecathode 6016. An ITO having a small work function due to addition of Limay be used so that the light can be emitted from the side of thecathode 6016, in addition to the method for making a film thicknesssmaller.

The transistor 6002 is a driving transistor for controlling a currentsupplied to the light emitting element 6019, and is connected to thelight emitting element 6019 in series directly or via another circuitelement.

The anode 6010 is formed on the third interlayer insulating film 6008. Abarrier film 6018 is formed over the third interlayer insulating film6008. An organic resin film, an inorganic insulating film, an insulatingfilm including Si—O bond and Si—CH_(X) bond formed by using a siloxanematerial as a start or the like can be used for the barrier film 6018.The barrier film 6018 has an opening portion 6017 and a light emittingelement 6019 is formed by laminating the anode 6010, the hole injectionlayer 6011, the hole transporting layer 6012, the light emitting layer6013, the electron transporting layer 6014, the electron injection layer6015 and the cathode 6016 in the opening portion.

A protective film 6020 is formed over the cathode 6016. As well as thethird interlayer insulating film 6008, a film that prevents more amaterial promoting a deterioration of the light emitting element such asmoisture and oxygen from penetrating than other insulating films is usedas the protective film 6020. Typically, for example, a DLC film, acarbon nitride film, a silicon nitride film formed by the RF sputteringmethod or the like is preferably used. A laminate of the above-describedfilm through which the material such as moisture and oxygen is nottransmitted easily and a film through which the material such asmoisture and oxygen is transmitted easily can be used as the protectivefilm.

An end portion of the barrier film 6018 in the opening portion 6017 ispreferably allowed to have a round shape so that the hole injectionlayer 6011, the hole transporting layer 6012, the light emitting layer6013, the electron transporting layer 6014, the electron injection layer6015 do not have holes in the end portion thereof. Specifically, thecurvature radius of the curve line shown by the sectional face of theorganic resin film in the opening portion is preferably about from 0.2μm to 2 μm.

With the above structure, the coverage of the hole injection layer 6011,the hole transporting layer 6012, the light emitting layer 6013, theelectron transporting layer 6014, and the electron injection layer 6015,and the cathode 6016 that are formed later can be enhanced. Thus, it canbe prevented that the anode 6010 and the cathode 6016 may short-circuit.Moreover, by relieving the stress of each of the above-described layers,a defect that a light emitting region decreases, which is referred to asa shrinkage, can be reduced and the reliability can be thus enhanced.

Practically, when the device shown in FIG. 16 is completed, a protectivefilm (a laminate film, an ultraviolet curing resin or the like) having afavorable airtightness and less degasfication or a light-transmittingsubstrate for sealing is preferably used to package (seal) the deviceand not to expose the device to air. At the time, resin is filledtherein to enhance the adhesion of the substrate for sealing for thesake of preventing the substrate for sealing from peeling off in thestep of separating a second substrate.

FIG. 16 shows a light-emitting device before a covering material isbonded. In this embodiment, light emitted from the light-emittingelement 6019 is emitted toward the side of the covering material, as thearrow shows. However, the present invention is not limited thereto. Thelight emitted from the light-emitting element may be emitted toward theside of the card substrate. In this case, an image displayed in a pixelportion is seen from the side of the card substrate.

The light emitting device used in an IC card of the present invention isnot limited to the structure shown in FIG. 16.

EMBODIMENT 5

A configuration of an IC card of the present invention having a functionas an electronic book is described in this embodiment. FIG. 17 shows atop view of an IC card of this embodiment. In the IC card shown in FIG.17, reference numeral 1700 denotes a card body that incorporates an ICchip 1701 and a thin film integrated circuit 1702. The thin filmintegrated circuit 1702 includes a display device and information suchas characters that is input from the external of the IC card can bedisplayed by a display portion 1703 of the display device.

Note that the IC card shown in FIG. 17 may be a contact type IC cardalthough it is a noncontact type IC card. In the case of a contact typeone, the size of an IC card is determined depending on a standard of aterminal device provided with a reader/writer. On the other hand, anoncontact type one does not necessarily follow a standard of a terminaldevice.

Text data such as characters has less information than images, and thus,power consumption in a noncontact type IC card can be suppressed bysending and receiving data. Further, the text data such as characterscan be displayed as a still image, and thus power consumption fordisplaying it can be suppressed.

This application is based on Japanese Patent Application Ser. no.2003-305805 filed in Japan Patent Office on 29^(th), Aug. 2003, thecontents of which are hereby incorporated by reference.

Although the present invention has been fully described by way ofEmbodiment Modes and Embodiments with reference to the accompanyingdrawings, it is to be understood that various changes and modificationswill be apparent to those skilled in the art. Therefore, unless suchchanges and modifications depart from the scope of the present inventionhereinafter defined, they should be constructed as being includedtherein.

1. An IC card comprising: a first single crystal integrated circuit; asecond integrated circuit; and a display device, wherein the secondintegrated circuit and the display device are each formed from a thinfilm semiconductor film, over a plastic substrate; and wherein the firstsingle crystal integrated circuit is mounted over the plastic substrateso as to be electrically connected to the second integrated circuit.